Amir Mostafapour - Assistant Professor, Faculty of Mechanical Engineering, University of Tabriz, Tabriz, Iran
Milad Mohammadi - University of Tabriz, Tabriz, Iran
Ali Ebrahimpour - Assistant professor, Mianeh Technical and Engineering Faculty, University of Tabriz, Mianeh, Iran

A full factorial design of experiment was applied running ۳۶ experiments to investigate the effects of milling parameters including cutting speed with three levels of ۶۲.۸۳, ۹۴.۲۴ and ۱۲۵.۶۶ m/min, feed rate with three levels of ۰.۱, ۰.۲ and ۰.۳ mm/tooth, cutting depth with two levels of ۰.۵ and ۱ mm and machining media with two levels, on surface integration properties of magnesium AZ۹۱C alloy such as grain size, secondary phase percent, surface microhardness and surface roughness. In all cases, a fine grained surface with higher secondary phase sediment and microhardness obtained comparing the raw material. According to analysis of variance results, the most effective parameter on grain size, secondary phase percent and microhardness was cutting depth and the most effective parameter on surface roughness was feed rate. although the grain size in all machined samples was smaller than that of the raw material but due to the dual effect of cryogenic conditions, which both cool and lubricate and reduce the temperature and strain rate at the same time, the direct effect of this parameter on grain size was not significant. Also, the all interaction effects of parameters on grain size and microhardness were significant.

Milling, Surface roughness, Grain size, DOE, ANOVA, Magnesium alloy AZ۹۱